//jpeg_encoder_basic.js -- https://github.com/owencm/javascript-jpeg-encoder/blob/master/jpeg_encoder_basic.js
function JPEGEncoder(quality) {
	var self = this;
	var fround = Math.round;
	var ffloor = Math.floor;
	var YTable = new Array(64);
	var UVTable = new Array(64);
	var fdtbl_Y = new Array(64);
	var fdtbl_UV = new Array(64);
	var YDC_HT;
	var UVDC_HT;
	var YAC_HT;
	var UVAC_HT;

	var bitcode = new Array(65535);
	var category = new Array(65535);
	var outputfDCTQuant = new Array(64);
	var DU = new Array(64);
	var byteout = [];
	var bytenew = 0;
	var bytepos = 7;

	var YDU = new Array(64);
	var UDU = new Array(64);
	var VDU = new Array(64);
	var clt = new Array(256);
	var RGB_YUV_TABLE = new Array(2048);
	var currentQuality;

	var ZigZag = [ 0, 1, 5, 6, 14, 15, 27, 28, 2, 4, 7, 13, 16, 26, 29, 42, 3,
			8, 12, 17, 25, 30, 41, 43, 9, 11, 18, 24, 31, 40, 44, 53, 10, 19,
			23, 32, 39, 45, 52, 54, 20, 22, 33, 38, 46, 51, 55, 60, 21, 34, 37,
			47, 50, 56, 59, 61, 35, 36, 48, 49, 57, 58, 62, 63 ];

	var std_dc_luminance_nrcodes = [ 0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0,
			0, 0, 0 ];
	var std_dc_luminance_values = [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 ];
	var std_ac_luminance_nrcodes = [ 0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0,
			0, 1, 0x7d ];
	var std_ac_luminance_values = [ 0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05,
			0x12, 0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07, 0x22, 0x71,
			0x14, 0x32, 0x81, 0x91, 0xa1, 0x08, 0x23, 0x42, 0xb1, 0xc1, 0x15,
			0x52, 0xd1, 0xf0, 0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16,
			0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x34,
			0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47,
			0x48, 0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a,
			0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x73, 0x74, 0x75,
			0x76, 0x77, 0x78, 0x79, 0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88,
			0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a,
			0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3,
			0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,
			0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7,
			0xd8, 0xd9, 0xda, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8,
			0xe9, 0xea, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9,
			0xfa ];

	var std_dc_chrominance_nrcodes = [ 0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0,
			0, 0, 0, 0 ];
	var std_dc_chrominance_values = [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 ];
	var std_ac_chrominance_nrcodes = [ 0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4,
			0, 1, 2, 0x77 ];
	var std_ac_chrominance_values = [ 0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05,
			0x21, 0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71, 0x13, 0x22,
			0x32, 0x81, 0x08, 0x14, 0x42, 0x91, 0xa1, 0xb1, 0xc1, 0x09, 0x23,
			0x33, 0x52, 0xf0, 0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34,
			0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26, 0x27, 0x28, 0x29,
			0x2a, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x43, 0x44, 0x45, 0x46,
			0x47, 0x48, 0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
			0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x73, 0x74,
			0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86,
			0x87, 0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,
			0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa,
			0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,
			0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4, 0xd5,
			0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7,
			0xe8, 0xe9, 0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9,
			0xfa ];

function initQuantTables(sf){
			var YQT = [
				16, 11, 10, 16, 24, 40, 51, 61,
				12, 12, 14, 19, 26, 58, 60, 55,
				14, 13, 16, 24, 40, 57, 69, 56,
				14, 17, 22, 29, 51, 87, 80, 62,
				18, 22, 37, 56, 68,109,103, 77,
				24, 35, 55, 64, 81,104,113, 92,
				49, 64, 78, 87,103,121,120,101,
				72, 92, 95, 98,112,100,103, 99
			];

			for (var i = 0; i < 64; i++) {
				var t = ffloor((YQT[i]*sf+50)/100);
				if (t < 1) {
					t = 1;
				} else if (t > 255) {
					t = 255;
				}
				YTable[ZigZag[i]] = t;
			}
			var UVQT = [
				17, 18, 24, 47, 99, 99, 99, 99,
				18, 21, 26, 66, 99, 99, 99, 99,
				24, 26, 56, 99, 99, 99, 99, 99,
				47, 66, 99, 99, 99, 99, 99, 99,
				99, 99, 99, 99, 99, 99, 99, 99,
				99, 99, 99, 99, 99, 99, 99, 99,
				99, 99, 99, 99, 99, 99, 99, 99,
				99, 99, 99, 99, 99, 99, 99, 99
			];
			for (var j = 0; j < 64; j++) {
				var u = ffloor((UVQT[j]*sf+50)/100);
				if (u < 1) {
					u = 1;
				} else if (u > 255) {
					u = 255;
				}
				UVTable[ZigZag[j]] = u;
			}
			var aasf = [
				1.0, 1.387039845, 1.306562965, 1.175875602,
				1.0, 0.785694958, 0.541196100, 0.275899379
			];
			var k = 0;
			for (var row = 0; row < 8; row++)
			{
				for (var col = 0; col < 8; col++)
				{
					fdtbl_Y[k]  = (1.0 / (YTable [ZigZag[k]] * aasf[row] * aasf[col] * 8.0));
					fdtbl_UV[k] = (1.0 / (UVTable[ZigZag[k]] * aasf[row] * aasf[col] * 8.0));
					k++;
				}
			}
		}

		function computeHuffmanTbl(nrcodes, std_table){
			var codevalue = 0;
			var pos_in_table = 0;
			var HT = new Array();
			for (var k = 1; k <= 16; k++) {
				for (var j = 1; j <= nrcodes[k]; j++) {
					HT[std_table[pos_in_table]] = [];
					HT[std_table[pos_in_table]][0] = codevalue;
					HT[std_table[pos_in_table]][1] = k;
					pos_in_table++;
					codevalue++;
				}
				codevalue*=2;
			}
			return HT;
		}

		function initHuffmanTbl()
		{
			YDC_HT = computeHuffmanTbl(std_dc_luminance_nrcodes,std_dc_luminance_values);
			UVDC_HT = computeHuffmanTbl(std_dc_chrominance_nrcodes,std_dc_chrominance_values);
			YAC_HT = computeHuffmanTbl(std_ac_luminance_nrcodes,std_ac_luminance_values);
			UVAC_HT = computeHuffmanTbl(std_ac_chrominance_nrcodes,std_ac_chrominance_values);
		}

		function initCategoryNumber()
		{
			var nrlower = 1;
			var nrupper = 2;
			for (var cat = 1; cat <= 15; cat++) {
				// Positive numbers
				for (var nr = nrlower; nr<nrupper; nr++) {
					category[32767+nr] = cat;
					bitcode[32767+nr] = [];
					bitcode[32767+nr][1] = cat;
					bitcode[32767+nr][0] = nr;
				}
				// Negative numbers
				for (var nrneg =-(nrupper-1); nrneg<=-nrlower; nrneg++) {
					category[32767+nrneg] = cat;
					bitcode[32767+nrneg] = [];
					bitcode[32767+nrneg][1] = cat;
					bitcode[32767+nrneg][0] = nrupper-1+nrneg;
				}
				nrlower <<= 1;
				nrupper <<= 1;
			}
		}

		function initRGBYUVTable() {
			for(var i = 0; i < 256;i++) {
				RGB_YUV_TABLE[i]      		=  19595 * i;
				RGB_YUV_TABLE[(i+ 256)>>0] 	=  38470 * i;
				RGB_YUV_TABLE[(i+ 512)>>0] 	=   7471 * i + 0x8000;
				RGB_YUV_TABLE[(i+ 768)>>0] 	= -11059 * i;
				RGB_YUV_TABLE[(i+1024)>>0] 	= -21709 * i;
				RGB_YUV_TABLE[(i+1280)>>0] 	=  32768 * i + 0x807FFF;
				RGB_YUV_TABLE[(i+1536)>>0] 	= -27439 * i;
				RGB_YUV_TABLE[(i+1792)>>0] 	= - 5329 * i;
			}
		}

		// IO functions
		function writeBits(bs)
		{
			var value = bs[0];
			var posval = bs[1]-1;
			while ( posval >= 0 ) {
				if (value & (1 << posval) ) {
					bytenew |= (1 << bytepos);
				}
				posval--;
				bytepos--;
				if (bytepos < 0) {
					if (bytenew == 0xFF) {
						writeByte(0xFF);
						writeByte(0);
					}
					else {
						writeByte(bytenew);
					}
					bytepos=7;
					bytenew=0;
				}
			}
		}

		function writeByte(value)
		{
			byteout.push(clt[value]); // write char directly instead of
										// converting later
		}

		function writeWord(value)
		{
			writeByte((value>>8)&0xFF);
			writeByte((value   )&0xFF);
		}

		// DCT & quantization core
		function fDCTQuant(data, fdtbl)
		{
			var d0, d1, d2, d3, d4, d5, d6, d7;
			/* Pass 1: process rows. */
			var dataOff=0;
			var i;
			const I8 = 8;
			const I64 = 64;
			for (i=0; i<I8; ++i)
			{
				d0 = data[dataOff];
				d1 = data[dataOff+1];
				d2 = data[dataOff+2];
				d3 = data[dataOff+3];
				d4 = data[dataOff+4];
				d5 = data[dataOff+5];
				d6 = data[dataOff+6];
				d7 = data[dataOff+7];

				var tmp0 = d0 + d7;
				var tmp7 = d0 - d7;
				var tmp1 = d1 + d6;
				var tmp6 = d1 - d6;
				var tmp2 = d2 + d5;
				var tmp5 = d2 - d5;
				var tmp3 = d3 + d4;
				var tmp4 = d3 - d4;

				/* Even part */
				var tmp10 = tmp0 + tmp3;	/* phase 2 */
				var tmp13 = tmp0 - tmp3;
				var tmp11 = tmp1 + tmp2;
				var tmp12 = tmp1 - tmp2;

				data[dataOff] = tmp10 + tmp11; /* phase 3 */
				data[dataOff+4] = tmp10 - tmp11;

				var z1 = (tmp12 + tmp13) * 0.707106781; /* c4 */
				data[dataOff+2] = tmp13 + z1; /* phase 5 */
				data[dataOff+6] = tmp13 - z1;

				/* Odd part */
				tmp10 = tmp4 + tmp5; /* phase 2 */
				tmp11 = tmp5 + tmp6;
				tmp12 = tmp6 + tmp7;

				/*
				 * The rotator is modified from fig 4-8 to avoid extra
				 * negations.
				 */
				var z5 = (tmp10 - tmp12) * 0.382683433; /* c6 */
				var z2 = 0.541196100 * tmp10 + z5; /* c2-c6 */
				var z4 = 1.306562965 * tmp12 + z5; /* c2+c6 */
				var z3 = tmp11 * 0.707106781; /* c4 */

				var z11 = tmp7 + z3;	/* phase 5 */
				var z13 = tmp7 - z3;

				data[dataOff+5] = z13 + z2;	/* phase 6 */
				data[dataOff+3] = z13 - z2;
				data[dataOff+1] = z11 + z4;
				data[dataOff+7] = z11 - z4;

				dataOff += 8; /* advance pointer to next row */
			}

			/* Pass 2: process columns. */
			dataOff = 0;
			for (i=0; i<I8; ++i)
			{
				d0 = data[dataOff];
				d1 = data[dataOff + 8];
				d2 = data[dataOff + 16];
				d3 = data[dataOff + 24];
				d4 = data[dataOff + 32];
				d5 = data[dataOff + 40];
				d6 = data[dataOff + 48];
				d7 = data[dataOff + 56];

				var tmp0p2 = d0 + d7;
				var tmp7p2 = d0 - d7;
				var tmp1p2 = d1 + d6;
				var tmp6p2 = d1 - d6;
				var tmp2p2 = d2 + d5;
				var tmp5p2 = d2 - d5;
				var tmp3p2 = d3 + d4;
				var tmp4p2 = d3 - d4;

				/* Even part */
				var tmp10p2 = tmp0p2 + tmp3p2;	/* phase 2 */
				var tmp13p2 = tmp0p2 - tmp3p2;
				var tmp11p2 = tmp1p2 + tmp2p2;
				var tmp12p2 = tmp1p2 - tmp2p2;

				data[dataOff] = tmp10p2 + tmp11p2; /* phase 3 */
				data[dataOff+32] = tmp10p2 - tmp11p2;

				var z1p2 = (tmp12p2 + tmp13p2) * 0.707106781; /* c4 */
				data[dataOff+16] = tmp13p2 + z1p2; /* phase 5 */
				data[dataOff+48] = tmp13p2 - z1p2;

				/* Odd part */
				tmp10p2 = tmp4p2 + tmp5p2; /* phase 2 */
				tmp11p2 = tmp5p2 + tmp6p2;
				tmp12p2 = tmp6p2 + tmp7p2;

				/*
				 * The rotator is modified from fig 4-8 to avoid extra
				 * negations.
				 */
				var z5p2 = (tmp10p2 - tmp12p2) * 0.382683433; /* c6 */
				var z2p2 = 0.541196100 * tmp10p2 + z5p2; /* c2-c6 */
				var z4p2 = 1.306562965 * tmp12p2 + z5p2; /* c2+c6 */
				var z3p2 = tmp11p2 * 0.707106781; /* c4 */

				var z11p2 = tmp7p2 + z3p2;	/* phase 5 */
				var z13p2 = tmp7p2 - z3p2;

				data[dataOff+40] = z13p2 + z2p2; /* phase 6 */
				data[dataOff+24] = z13p2 - z2p2;
				data[dataOff+ 8] = z11p2 + z4p2;
				data[dataOff+56] = z11p2 - z4p2;

				dataOff++; /* advance pointer to next column */
			}

			// Quantize/descale the coefficients
			var fDCTQuant;
			for (i=0; i<I64; ++i)
			{
				// Apply the quantization and scaling factor & Round to nearest
				// integer
				fDCTQuant = data[i]*fdtbl[i];
				outputfDCTQuant[i] = (fDCTQuant > 0.0) ? ((fDCTQuant + 0.5)|0) : ((fDCTQuant - 0.5)|0);
				// outputfDCTQuant[i] = fround(fDCTQuant);

			}
			return outputfDCTQuant;
		}

		function writeAPP0()
		{
			writeWord(0xFFE0); // marker
			writeWord(16); // length
			writeByte(0x4A); // J
			writeByte(0x46); // F
			writeByte(0x49); // I
			writeByte(0x46); // F
			writeByte(0); // = "JFIF",'\0'
			writeByte(1); // versionhi
			writeByte(1); // versionlo
			writeByte(0); // xyunits
			writeWord(1); // xdensity
			writeWord(1); // ydensity
			writeByte(0); // thumbnwidth
			writeByte(0); // thumbnheight
		}

		function writeSOF0(width, height)
		{
			writeWord(0xFFC0); // marker
			writeWord(17);   // length, truecolor YUV JPG
			writeByte(8);    // precision
			writeWord(height);
			writeWord(width);
			writeByte(3);    // nrofcomponents
			writeByte(1);    // IdY
			writeByte(0x11); // HVY
			writeByte(0);    // QTY
			writeByte(2);    // IdU
			writeByte(0x11); // HVU
			writeByte(1);    // QTU
			writeByte(3);    // IdV
			writeByte(0x11); // HVV
			writeByte(1);    // QTV
		}

		function writeDQT()
		{
			writeWord(0xFFDB); // marker
			writeWord(132);	   // length
			writeByte(0);
			for (var i=0; i<64; i++) {
				writeByte(YTable[i]);
			}
			writeByte(1);
			for (var j=0; j<64; j++) {
				writeByte(UVTable[j]);
			}
		}

		function writeDHT()
		{
			writeWord(0xFFC4); // marker
			writeWord(0x01A2); // length

			writeByte(0); // HTYDCinfo
			for (var i=0; i<16; i++) {
				writeByte(std_dc_luminance_nrcodes[i+1]);
			}
			for (var j=0; j<=11; j++) {
				writeByte(std_dc_luminance_values[j]);
			}

			writeByte(0x10); // HTYACinfo
			for (var k=0; k<16; k++) {
				writeByte(std_ac_luminance_nrcodes[k+1]);
			}
			for (var l=0; l<=161; l++) {
				writeByte(std_ac_luminance_values[l]);
			}

			writeByte(1); // HTUDCinfo
			for (var m=0; m<16; m++) {
				writeByte(std_dc_chrominance_nrcodes[m+1]);
			}
			for (var n=0; n<=11; n++) {
				writeByte(std_dc_chrominance_values[n]);
			}

			writeByte(0x11); // HTUACinfo
			for (var o=0; o<16; o++) {
				writeByte(std_ac_chrominance_nrcodes[o+1]);
			}
			for (var p=0; p<=161; p++) {
				writeByte(std_ac_chrominance_values[p]);
			}
		}

		function writeSOS()
		{
			writeWord(0xFFDA); // marker
			writeWord(12); // length
			writeByte(3); // nrofcomponents
			writeByte(1); // IdY
			writeByte(0); // HTY
			writeByte(2); // IdU
			writeByte(0x11); // HTU
			writeByte(3); // IdV
			writeByte(0x11); // HTV
			writeByte(0); // Ss
			writeByte(0x3f); // Se
			writeByte(0); // Bf
		}

		function processDU(CDU, fdtbl, DC, HTDC, HTAC){
			var EOB = HTAC[0x00];
			var M16zeroes = HTAC[0xF0];
			var pos;
			const I16 = 16;
			const I63 = 63;
			const I64 = 64;
			var DU_DCT = fDCTQuant(CDU, fdtbl);
			// ZigZag reorder
			for (var j=0;j<I64;++j) {
				DU[ZigZag[j]]=DU_DCT[j];
			}
			var Diff = DU[0] - DC; DC = DU[0];
			// Encode DC
			if (Diff==0) {
				writeBits(HTDC[0]); // Diff might be 0
			} else {
				pos = 32767+Diff;
				writeBits(HTDC[category[pos]]);
				writeBits(bitcode[pos]);
			}
			// Encode ACs
			var end0pos = 63; // was const... which is crazy
			for (; (end0pos>0)&&(DU[end0pos]==0); end0pos--) {};
			// end0pos = first element in reverse order !=0
			if ( end0pos == 0) {
				writeBits(EOB);
				return DC;
			}
			var i = 1;
			var lng;
			while ( i <= end0pos ) {
				var startpos = i;
				for (; (DU[i]==0) && (i<=end0pos); ++i) {}
				var nrzeroes = i-startpos;
				if ( nrzeroes >= I16 ) {
					lng = nrzeroes>>4;
					for (var nrmarker=1; nrmarker <= lng; ++nrmarker)
						writeBits(M16zeroes);
					nrzeroes = nrzeroes&0xF;
				}
				pos = 32767+DU[i];
				writeBits(HTAC[(nrzeroes<<4)+category[pos]]);
				writeBits(bitcode[pos]);
				i++;
			}
			if ( end0pos != I63 ) {
				writeBits(EOB);
			}
			return DC;
		}

		function initCharLookupTable(){
			var sfcc = String.fromCharCode;
			for(var i=0; i < 256; i++){ // /// ACHTUNG // 255
				clt[i] = sfcc(i);
			}
		}

		this.encode = function(image,quality) // image data object
		{
			var time_start = new Date().getTime();

			if(quality) setQuality(quality);

			// Initialize bit writer
			byteout = new Array();
			bytenew=0;
			bytepos=7;

			// Add JPEG headers
			writeWord(0xFFD8); // SOI
			writeAPP0();
			writeDQT();
			writeSOF0(image.width,image.height);
			writeDHT();
			writeSOS();


			// Encode 8x8 macroblocks
			var DCY=0;
			var DCU=0;
			var DCV=0;

			bytenew=0;
			bytepos=7;


			this.encode.displayName = "_encode_";

			var imageData = image.data;
			var width = image.width;
			var height = image.height;

			var quadWidth = width*4;
			var tripleWidth = width*3;

			var x, y = 0;
			var r, g, b;
			var start,p, col,row,pos;
			while(y < height){
				x = 0;
				while(x < quadWidth){
				start = quadWidth * y + x;
				p = start;
				col = -1;
				row = 0;

				for(pos=0; pos < 64; pos++){
					row = pos >> 3;// /8
					col = ( pos & 7 ) * 4; // %8
					p = start + ( row * quadWidth ) + col;		

					if(y+row >= height){ // padding bottom
						p-= (quadWidth*(y+1+row-height));
					}

					if(x+col >= quadWidth){ // padding right
						p-= ((x+col) - quadWidth +4)
					}

					r = imageData[ p++ ];
					g = imageData[ p++ ];
					b = imageData[ p++ ];


					/*
					 * // calculate YUV values dynamically YDU[pos]=(((
					 * 0.29900)*r+( 0.58700)*g+( 0.11400)*b))-128; //-0x80
					 * UDU[pos]=(((-0.16874)*r+(-0.33126)*g+( 0.50000)*b));
					 * VDU[pos]=((( 0.50000)*r+(-0.41869)*g+(-0.08131)*b));
					 */

					// use lookup table (slightly faster)
					YDU[pos] = ((RGB_YUV_TABLE[r]             + RGB_YUV_TABLE[(g +  256)>>0] + RGB_YUV_TABLE[(b +  512)>>0]) >> 16)-128;
					UDU[pos] = ((RGB_YUV_TABLE[(r +  768)>>0] + RGB_YUV_TABLE[(g + 1024)>>0] + RGB_YUV_TABLE[(b + 1280)>>0]) >> 16)-128;
					VDU[pos] = ((RGB_YUV_TABLE[(r + 1280)>>0] + RGB_YUV_TABLE[(g + 1536)>>0] + RGB_YUV_TABLE[(b + 1792)>>0]) >> 16)-128;

				}

				DCY = processDU(YDU, fdtbl_Y, DCY, YDC_HT, YAC_HT);
				DCU = processDU(UDU, fdtbl_UV, DCU, UVDC_HT, UVAC_HT);
				DCV = processDU(VDU, fdtbl_UV, DCV, UVDC_HT, UVAC_HT);
				x+=32;
				}
				y+=8;
			}


			// //////////////////////////////////////////////////////////////

			// Do the bit alignment of the EOI marker
			if ( bytepos >= 0 ) {
				var fillbits = [];
				fillbits[1] = bytepos+1;
				fillbits[0] = (1<<(bytepos+1))-1;
				writeBits(fillbits);
			}

			writeWord(0xFFD9); // EOI

			var jpegDataUri = 'data:image/jpeg;base64,' + btoa(byteout.join(''));

			byteout = [];

			// benchmarking
			var duration = new Date().getTime() - time_start;
    		console.log('Encoding time: '+ duration + 'ms');
    		//

			return jpegDataUri			
	}

	function setQuality(quality){
		if (quality <= 0) {
			quality = 1;
		}
		if (quality > 100) {
			quality = 100;
		}

		if(currentQuality == quality) return // don't recalc if unchanged

		var sf = 0;
		if (quality < 50) {
			sf = Math.floor(5000 / quality);
		} else {
			sf = Math.floor(200 - quality*2);
		}

		initQuantTables(sf);
		currentQuality = quality;
		console.log('Quality set to: '+quality +'%');
	}

	function init(){
		var time_start = new Date().getTime();
		if(!quality) quality = 50;
		// Create tables
		initCharLookupTable()
		initHuffmanTbl();
		initCategoryNumber();
		initRGBYUVTable();

		setQuality(quality);
		var duration = new Date().getTime() - time_start;
    	console.log('Initialization '+ duration + 'ms');
	}

	init();

};

// helper function to get the imageData of an existing image on the current
// page.
function getImageDataFromImage(idOrElement){
	var theImg = (typeof(idOrElement)=='string')? document.getElementById(idOrElement):idOrElement;
	var cvs = document.createElement('canvas');
	cvs.width = theImg.width;
	cvs.height = theImg.height;
	var ctx = cvs.getContext("2d");
	ctx.drawImage(theImg,0,0);

	return (ctx.getImageData(0, 0, cvs.width, cvs.height));
}
/*
 * 
 * function init(qu){ var theImg = document.getElementById('testimage'); var cvs =
 * document.createElement('canvas'); cvs.width = theImg.width; cvs.height =
 * theImg.height;
 * 
 * //document.body.appendChild(cvs);
 * 
 * var ctx = cvs.getContext("2d");
 * 
 * ctx.drawImage(theImg,0,0);
 * 
 * var theImgData = (ctx.getImageData(0, 0, cvs.width, cvs.height));
 * 
 * 
 * var jpegURI = encoder.encode(theImgData,qu);
 * 
 * var img = document.createElement('img'); img.src = jpegURI;
 * document.body.appendChild(img); }
 */

//https://github.com/stomita/ios-imagefile-megapixel/blob/master/src/megapix-image.js

/**
 * Mega pixel image rendering library for iOS6 Safari
 * 
 * Fixes iOS6 Safari's image file rendering issue for large size image (over
 * mega-pixel), which causes unexpected subsampling when drawing it in canvas.
 * By using this library, you can safely render the image with proper
 * stretching.
 * 
 * Copyright (c) 2012 Shinichi Tomita <shinichi.tomita@gmail.com> Released under
 * the MIT license
 */
(function() {

  /**
	 * Detect subsampling in loaded image. In iOS, larger images than 2M pixels
	 * may be subsampled in rendering.
	 */
  function detectSubsampling(img) {
    var iw = img.naturalWidth, ih = img.naturalHeight;
    if (iw * ih > 1024 * 1024) { // subsampling may happen over megapixel
									// image
      var canvas = document.createElement('canvas');
      canvas.width = canvas.height = 1;
      var ctx = canvas.getContext('2d');
      ctx.drawImage(img, -iw + 1, 0);
      // subsampled image becomes half smaller in rendering size.
      // check alpha channel value to confirm image is covering edge pixel or
		// not.
      // if alpha value is 0 image is not covering, hence subsampled.
      return ctx.getImageData(0, 0, 1, 1).data[3] === 0;
    } else {
      return false;
    }
  }

  /**
	 * Detecting vertical squash in loaded image. Fixes a bug which squash image
	 * vertically while drawing into canvas for some images.
	 */
  function detectVerticalSquash(img, iw, ih) {
    var canvas = document.createElement('canvas');
    canvas.width = 1;
    canvas.height = ih;
    var ctx = canvas.getContext('2d');
    ctx.drawImage(img, 0, 0);
    var data = ctx.getImageData(0, 0, 1, ih).data;
    // search image edge pixel position in case it is squashed vertically.
    var sy = 0;
    var ey = ih;
    var py = ih;
    while (py > sy) {
      var alpha = data[(py - 1) * 4 + 3];
      if (alpha === 0) {
        ey = py;
      } else {
        sy = py;
      }
      py = (ey + sy) >> 1;
    }
    var ratio = (py / ih);
    return (ratio===0)?1:ratio;
  }

  /**
	 * Rendering image element (with resizing) and get its data URL
	 */
  function renderImageToDataURL(img, options, doSquash) {
    var canvas = document.createElement('canvas');
    renderImageToCanvas(img, canvas, options, doSquash);
    return canvas.toDataURL("image/jpeg", options.quality || 0.8);
  }

  /**
	 * Rendering image element (with resizing) into the canvas element
	 */
  function renderImageToCanvas(img, canvas, options, doSquash) {
    var iw = img.naturalWidth, ih = img.naturalHeight;
    var width = options.width, height = options.height;
    var ctx = canvas.getContext('2d');
    ctx.save();
    transformCoordinate(canvas, ctx, width, height, options.orientation);
    var subsampled = detectSubsampling(img);
    if (subsampled) {
      iw /= 2;
      ih /= 2;
    }
    var d = 1024; // size of tiling canvas
    var tmpCanvas = document.createElement('canvas');
    tmpCanvas.width = tmpCanvas.height = d;
    var tmpCtx = tmpCanvas.getContext('2d');
    var vertSquashRatio = doSquash ? detectVerticalSquash(img, iw, ih) : 1;
    var dw = Math.ceil(d * width / iw);
    var dh = Math.ceil(d * height / ih / vertSquashRatio);
    var sy = 0;
    var dy = 0;
    while (sy < ih) {
      var sx = 0;
      var dx = 0;
      while (sx < iw) {
        tmpCtx.clearRect(0, 0, d, d);
        tmpCtx.drawImage(img, -sx, -sy);
        ctx.drawImage(tmpCanvas, 0, 0, d, d, dx, dy, dw, dh);
        sx += d;
        dx += dw;
      }
      sy += d;
      dy += dh;
    }
    ctx.restore();
    tmpCanvas = tmpCtx = null;
  }

  /**
	 * Transform canvas coordination according to specified frame size and
	 * orientation Orientation value is from EXIF tag
	 */
  function transformCoordinate(canvas, ctx, width, height, orientation) {
    switch (orientation) {
      case 5:
      case 6:
      case 7:
      case 8:
        canvas.width = height;
        canvas.height = width;
        break;
      default:
        canvas.width = width;
        canvas.height = height;
    }
    switch (orientation) {
      case 2:
        // horizontal flip
        ctx.translate(width, 0);
        ctx.scale(-1, 1);
        break;
      case 3:
        // 180 rotate left
        ctx.translate(width, height);
        ctx.rotate(Math.PI);
        break;
      case 4:
        // vertical flip
        ctx.translate(0, height);
        ctx.scale(1, -1);
        break;
      case 5:
        // vertical flip + 90 rotate right
        ctx.rotate(0.5 * Math.PI);
        ctx.scale(1, -1);
        break;
      case 6:
        // 90 rotate right
        ctx.rotate(0.5 * Math.PI);
        ctx.translate(0, -height);
        break;
      case 7:
        // horizontal flip + 90 rotate right
        ctx.rotate(0.5 * Math.PI);
        ctx.translate(width, -height);
        ctx.scale(-1, 1);
        break;
      case 8:
        // 90 rotate left
        ctx.rotate(-0.5 * Math.PI);
        ctx.translate(-width, 0);
        break;
      default:
        break;
    }
  }


  /**
	 * MegaPixImage class
	 */
  function MegaPixImage(srcImage) {
    if (window.Blob && srcImage instanceof Blob) {
      var img = new Image();
      var URL = window.URL && window.URL.createObjectURL ? window.URL :
                window.webkitURL && window.webkitURL.createObjectURL ? window.webkitURL :
                null;
      if (!URL) { throw Error("No createObjectURL function found to create blob url"); }
      img.src = URL.createObjectURL(srcImage);
      this.blob = srcImage;
      srcImage = img;
    }
    if (!srcImage.naturalWidth && !srcImage.naturalHeight) {
      var _this = this;
      srcImage.onload = function() {
        var listeners = _this.imageLoadListeners;
        if (listeners) {
          _this.imageLoadListeners = null;
          for (var i=0, len=listeners.length; i<len; i++) {
            listeners[i]();
          }
        }
      };
      this.imageLoadListeners = [];
    }
    this.srcImage = srcImage;
  }

  /**
	 * Rendering megapix image into specified target element
	 */
  MegaPixImage.prototype.render = function(target, options) {
    if (this.imageLoadListeners) {
      var _this = this;
      this.imageLoadListeners.push(function() { _this.render(target, options) });
      return;
    }
    options = options || {};
    var imgWidth = this.srcImage.naturalWidth, imgHeight = this.srcImage.naturalHeight,
        width = options.width, height = options.height,
        maxWidth = options.maxWidth, maxHeight = options.maxHeight,
        doSquash = !this.blob || this.blob.type === 'image/jpeg';
    if (width && !height) {
      height = (imgHeight * width / imgWidth) << 0;
    } else if (height && !width) {
      width = (imgWidth * height / imgHeight) << 0;
    } else {
      width = imgWidth;
      height = imgHeight;
    }
    if (maxWidth && width > maxWidth) {
      width = maxWidth;
      height = (imgHeight * width / imgWidth) << 0;
    }
    if (maxHeight && height > maxHeight) {
      height = maxHeight;
      width = (imgWidth * height / imgHeight) << 0;
    }
    var opt = { width : width, height : height };
    for (var k in options) opt[k] = options[k];

    var tagName = target.tagName.toLowerCase();
    if (tagName === 'img') {
      target.src = renderImageToDataURL(this.srcImage, opt, doSquash);
    } else if (tagName === 'canvas') {
      renderImageToCanvas(this.srcImage, target, opt, doSquash);
    }
    if (typeof this.onrender === 'function') {
      this.onrender(target);
    }
  };

  /**
	 * Export class to global
	 */
  if (typeof define === 'function' && define.amd) {
    define([], function() { return MegaPixImage; }); // for AMD loader
  } else {
    this.MegaPixImage = MegaPixImage;
  }

})();